import java.util.Arrays;
public class Test {

    public int[] elem;
    public int usedSize;
    public Test() {
        this.elem = new int[10];
    }

    /**
     * 填充数据
     * @param array
     */
    public void initElem(int[] array) {
        for(int i = 0;i < array.length;i++) {
            elem[i] = array[i];
            usedSize++;
        }
    }

    public void createBigHeap() {
        for(int parent = (usedSize-1-1)/2;parent >= 0;parent--) {
            shiftDown(parent,usedSize);
        }
    }
    /**
     * 向下调整
     * @param
     * @param parent
     */
    public void shiftDown(int parent,int end) {
        int child = 2*parent + 1;

        while(child < end) {
            //如果右孩子存在，找到左右孩子中较小的孩子，用child进行标记
            if(child+1 < usedSize && elem[child] < elem[child+1]) {
                child++;
            }
            //child一定是 左右孩子最大值的下标
            if(elem[child] > elem[parent]) {
                //交换
                swap(child,parent);
                parent = child;
                child = 2*parent+1;
            }else {
                break;
            }
        }
    }

    private void swap(int i,int j) {
        int tmp = elem[i];
        elem[i] = elem[j];
        elem[j] = tmp;
    }

    public int poll() {
        int tmp = elem[0];//删除嘴高的那个值
        swap(0,usedSize-1);
        usedSize--;
        shiftDown(0,usedSize);
        return tmp;
    }


    
    public void offer(int val) {
        //1.判断满
        if(isFull()) {
            //扩容
            this.elem = Arrays.copyOf(elem,2*elem.length);
        }
        //2.插入元素
        elem[usedSize] = val;
        usedSize++;
        //3.开始向上调整
        siftUp(usedSize-1);
    }

    private void siftUp(int child) {
        int parent = (child-1) / 2;
        while(child > 0) {
            if(elem[child] > elem[parent]) {
                swap(child,parent);
                child = parent;
                parent = (child-1)/2;
            }else {
                break;
            }
        }
    }

    public boolean isFull() {
        return usedSize == elem.length;
    }

    public void heapSort() {
        int end = usedSize-1;
        while(end > 0) {
            swap(0,end);
            shiftDown(0,end-1);
            end--;
        }
    }
}
